Single-sole sandal having fabric straps and method of attachment

ABSTRACT

A single-sole sandal having fabric straps includes a sole made of a pliable yet durable material and a “Y” shaped strap having a strap retention disc attached thereto so that the strap retention disc may be inserted through an aperture in the sole by deforming the sole, and the sole returns to its original shape to retain the strap in place.

RELATED APPLICATIONS

The present invention claims the benefit of priority to U.S. ProvisionalPatent Application Ser. No. 60/961,460, filed Jul. 20, 2007, with thesame title and currently co-pending.

BACKGROUND OF THE INVENTION

Sandals are a very popular form of footwear. The style and design ofsandals varies greatly between manufactures, and have evolved over theyears. For instance, one form of sandal that has become a favorite overthe last few decades is commonly referred to as the flip-flop.Flip-flops are the most basic of footwear and typically include a thinfoam rubber sole with two simple straps running in a “Y” from the sidesof the foot to join between the big toe and next toe. The basicflip-flop sandal is held on the foot by the straps passing over the topor around the sides of the foot. Flip-flops are typically made with apliable foam rubber sole, and molded rubber or plastic straps, mostcommonly known as “Zori's”. Popular use of flip-flops as simple warmclimate beach or outdoor wear has spread through much of the world. Anexample of a PRIOR ART flip-flop is shown in FIGS. 1 and 2:

FIG. 1 depicts the upper and lower views of a PRIOR ART flip flop andshows the sole, and the positioning and attachment of the strap; and

FIG. 2 is a cross-sectional view of the strap attachment to the sole,showing the strap and strap retention plug, and the plug receiver andthe plug bore as formed in the sole.

Referring to FIG. 1, a PRIOR ART flip-flop is shown and includes aplanar upper sole made from a pliable rubber compound, typicallyEthylene-vinyl acetate (also known as EVA); however other sole materialsmay be used. A rubber or plastic strap in the shape of a “Y” is attachedto the sole at its three endpoints to provide ample room for a wearer ofthe flip flop to insert his foot between the strap and the sole, withthe base of the “Y” being positioned between the big toe and adjacenttoe. The strap is secured to the sole with strap retention plugsextending through the flip flop.

FIG. 2 is a cross-sectional view of the attachment of the strap of thePRIOR ART flip flop. More specifically, the sole of the flip flop isformed with a plug bore passing perpendicularly through the sole andleading to a plug receiver sized to closely receive a strap retentionplug integrally formed on the end of the strap.

Attachment of the strap to the sole is accomplished by inserting thestrap retention plug through the plug bore in the sole in the downwarddirection. Due to the deformable nature of the rubber sole and the strapretention plug, the size of the plug bore may be much smaller than theretention plug. Once the strap retention plug is passed through the plugbore and through the sole of the flip flop, the strap is then drawnupwards so that the strap retention plug is received in the plugreceiver to form a smooth bottom surface of the flip flop.

One challenge with this method of construction is that the typicallocation of a failure of the flip flop occurs where the strap joins thestrap retention plug. This is due in large part to the extraordinarytensional forces exerted on the strap during the ordinary wearing of theflip flop. In other cases, the failure of the flip flop is due to theweakening of the sole adjacent the plug bore where the sole is thinner.In those cases, the strap retention plug will pull through the sole.

In light of the above, it would be advantageous to provide animprovement to the ordinary flip flop which overcomes many of thestructural deficiencies of the prior art flip flops, yet is equally ifnot more comfortable to wear, and equally if not more cost effective tomanufacture.

SUMMARY OF THE DRAWINGS

FIG. 1 depicts the upper and lower views of a PRIOR ART flip flop andshows the sole, and the positioning and attachment of the strap;

FIG. 2 is a cross-sectional view of the strap attachment to the sole,showing the strap and strap retention plug, and the plug receiver andthe plug bore as formed in the sole;

FIG. 3 is a perspective view of the upper portion of the flip flop ofthe present invention showing a sole, “Y” shaped a cloth or woven strapterminating at its endpoints with a strap attachment loop passingthrough the sole, and a perspective view of the lower portion of theflip flop showing the attachment loop passing through strap retentiondiscs which sit flush within disc receivers formed on the underside ofthe sole;

FIG. 4 is a cross-sectional view of the strap and its attachment to thesole of the present invention, showing the strap fastened to anattachment loop passing through the retention disc, and the retentiondisc and attachment loop being passed through the disc bore;

FIG. 5 is a cross-sectional view of the strap and its attachment to thesole of the present invention showing the strap fastened to theattachment loop passing through the retention disc, and the retentiondisc and attachment loop being pulled upwards seating the strapretention disc in the disc receiver formed in the underside of the sole.

DETAILED DESCRIPTION OF THE INVENTION

Referring to FIG. 3, the single sole sandal having fabric straps of thepresent invention is shown in a perspective view. This Figure provides aview of the upper portion of the flip flop and shows a roughlyfoot-shaped sole. This sole, in a preferred embodiment, is made fromEthylene-vinyl acetate (also known as EVA or sometimes simply as“acetate”) which is the copolymer of ethylene and vinyl acetate. EVA isa polymer that approaches elastomeric materials in softness andflexibility, yet can be processed like other thermoplastics thusproviding for use of well known injection molding and productiontechniques. The EVA material has good clarity and gloss, heat andmoisture barrier properties, low-temperature toughness, is stress andcrack resistant, and is resistant to UV radiation, and is thus ideal foroutdoor use by providing a lightweight and durable sole.

The present invention also includes a “Y” shaped strap shaped so thatone leg of the strap passes between the big toe and adjacent toe of thewearer, and the other two legs of the strap pass to the sides of thefoot and attach near the heel. In a preferred embodiment, the strap ismade from a cloth or woven material to provide for increased comfort andstrength. The cloth or woven strap terminates at its endpoints with astrap attachment loop. The strap attachment loop is fixedly attached,such as by sewing, to the ends of the strap, and captures a strapretention disc in the loop. Once the strap attachment loop is attachedto the strap, the strap retention disc is passed through the sole fromthe upper surface through to the bottom. Once the strap retention dischas been passed through the sole, the strap retention discs sits flushwithin disc receivers formed on the underside of the sole.

From FIG. 4, a cross-sectional view of the strap and its attachment tothe sole of the present invention is shown and illustrates the strapsecurely fastened to an attachment loop. The attachment loop passesthrough the retention disc to secure the retention disc to the strap. Asshown, the retention disc and attachment loop are passed downward in thedirection of the arrow through the disc bore formed in the sole. Thesole is sufficiently pliable to accommodate the passage of the retentiondisc through the sole without damage, and once past, the sole returns toits original shape.

Moving along to FIG. 5, a cross-sectional view of the strap and itsattachment to the sole of the present invention shows the strap fastenedto the attachment loop passing through the retention disc. The retentiondisc and attachment loop are then pulled upwards in the direction of thearrow towards the sole, seating the strap retention disc in the discreceiver formed in the underside of the sole.

The single sole sandal having fabric straps of the present invention asshown has a number of advantages over the prior art. For instance, thepresent invention provides for a more durable sandal as the straps areless likely to fail due the ordinary stresses of wear because thehigh-strength strap attachment loop and high-strength retention disc arefar stronger than the molded strap retention plug. Moreover, because thestrap retention disc is much thinner than the art strap retention plug,the depth of the disc receiver formed in the sole is much thinner thanthe plug receiver. As a result, the strength of the sole is notjeopardized.

Another advantage of the present invention is the attachment of a clothstrap to a single sole sandal. For instance, previously, in order toattach a cloth strap to a foam-soled sandal, the sandal would have to bemade with a two-part sandal where the cloth strap would insert through aslit in the upper layer of the sandal, and be captured between the upperand lower layer using an adhesive. The present invention, however,provides for the easy attachment of a cloth strap to a single-layeredsole.

It is to be understood that the single sole sandal having fabric strapsof the present invention as shown is merely exemplary of a preferredembodiment and that no limitations are implied except those specificallystated. It is to be appreciated that the various features andcooperation of those features discussed above are to be extended tosimilar structures and methods of manufacturing as is known in the art.

1. A single sole sandal, comprising: a Y-shaped strap having three legseach having an end; a sole formed of a single material and formed withan aperture to receive each said end; a strap retention disc having adiameter and attached to said end; wherein said diameter of said strapretention disc is larger than said aperture.